U.S. patent number 10,988,206 [Application Number 17/044,788] was granted by the patent office on 2021-04-27 for assistance system for facilitating operation of electric cycle.
This patent grant is currently assigned to Fu-Long Chang, YANGDING (TIANJIN) TECHNOLOGY CO., LTD.. The grantee listed for this patent is Fu-Long Chang, YANGDING (TIANJIN) TECHNOLOGY CO., LTD.. Invention is credited to Fu-Long Chang.
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United States Patent |
10,988,206 |
Chang |
April 27, 2021 |
Assistance system for facilitating operation of electric cycle
Abstract
An assistance system includes a resistance detecting unit
obtaining a resistance factor, a database storing starting torque
values and operating torque values, a torque calculation unit
including a controller, and a torque-control handlebar grip
operated to trigger an assigned gain and to tune the same to be
provided to the torque calculation unit. When switched to an aided
mode, the controller calculates a compensated torque value based on
one of the starting/operating torque values and the resistance
factor, calculates an output torque value by a product of the
compensated torque value, the assist ratio and the assigned gain,
and controls a torque motor to drive rotation of a driving wheel
based on the output torque value.
Inventors: |
Chang; Fu-Long (Chiayi,
TW) |
Applicant: |
Name |
City |
State |
Country |
Type |
YANGDING (TIANJIN) TECHNOLOGY CO., LTD.
Chang; Fu-Long |
Tianjin
Chiayi |
N/A
N/A |
CN
TW |
|
|
Assignee: |
YANGDING (TIANJIN) TECHNOLOGY CO.,
LTD. (Tianjin, CN)
Chang; Fu-Long (Chiayi, TW)
|
Family
ID: |
1000005513758 |
Appl.
No.: |
17/044,788 |
Filed: |
March 29, 2019 |
PCT
Filed: |
March 29, 2019 |
PCT No.: |
PCT/CN2019/080498 |
371(c)(1),(2),(4) Date: |
October 01, 2020 |
PCT
Pub. No.: |
WO2019/192404 |
PCT
Pub. Date: |
October 10, 2019 |
Foreign Application Priority Data
|
|
|
|
|
Apr 1, 2018 [CN] |
|
|
201810279882.8 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B62K
23/02 (20130101); B62M 6/50 (20130101); B62M
6/60 (20130101); B62J 45/20 (20200201); B62J
43/13 (20200201); B62L 3/02 (20130101); B62J
45/4151 (20200201); B62J 45/412 (20200201); B62M
6/90 (20130101); B62M 6/55 (20130101) |
Current International
Class: |
B62M
6/50 (20100101); B62M 6/60 (20100101); B62J
45/415 (20200101); B62L 3/02 (20060101); B62J
45/20 (20200101); B62J 45/412 (20200101); B62K
23/02 (20060101); B62J 43/13 (20200101); B62M
6/55 (20100101); B62M 6/90 (20100101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
102826160 |
|
Dec 2012 |
|
CN |
|
105574278 |
|
May 2016 |
|
CN |
|
108516039 |
|
Sep 2018 |
|
CN |
|
2621795 |
|
Aug 2013 |
|
EP |
|
2014193684 |
|
Oct 2014 |
|
JP |
|
Primary Examiner: Hurley; Kevin
Assistant Examiner: Arce; Marlon A
Attorney, Agent or Firm: Muncy, Geissler, Olds & Lowe,
P.C.
Claims
What is claimed is:
1. An assistance system for facilitating operation of an electric
cycle, the electric cycle including a cycle body, a driving wheel,
a cycle drivetrain, a battery, and a torque motor adapted to exert
torque to the driving wheel, said assistance system to be mounted
on the cycle body and to be electrically connected to the battery
and the torque motor, said assistance system comprising: a
resistance detecting unit configured to obtain a resistance factor
that works against forward movement of said electric cycle; a
database configured to store a set of starting torque values each
of which is a value of torque for initiating rotation of the
driving wheel from a standstill under influence of the resistance
factor, and a set of operating torque values each of which is a
value of torque for maintaining the rotation of the driving wheel
at a constant rotational speed under the influence of the
resistance factor; a torque calculation unit including a controller
switchable between an aided mode and an exercise mode; and a
torque-control handlebar grip configured to be operated to trigger
an assigned gain and to tune the assigned gain that is to be
provided to said torque calculation unit, wherein said controller
is configured to, when said controller is switched to the aided
mode, determine one of the starting torque values or one of the
operating torque values based on the resistance factor obtained by
said resistance detecting unit to serve as an assist torque value,
calculate a compensated torque value based on the assist torque
value and the resistance factor obtained by said resistance
detecting unit, multiply the compensated torque value by the
assigned gain, to obtain an output torque value, and control the
torque motor to drive the rotation of the driving wheel based on
the output torque value.
2. The assistance system as claimed in claim 1, further comprising:
a wheel speed sensor that is configured to detect the rotational
speed of the driving wheel, wherein each of the operating torque
values corresponds to a range of values of the rotational speed of
the driving wheel, and said controller is configured to, when the
rotational speed of the driving wheel thus detected is equal to
zero, determine one of the starting torque values based on the
resistance factor detected by said resistance detecting unit, and
when the rotational speed of the driving wheel thus detected is not
equal to zero, determine one of the operating torque values based
on the resistance factor detected by said resistance detecting unit
and the rotational speed of the driving wheel detected by said
wheel speed sensor.
3. The assistance system as claimed in claim 1, wherein: said
resistance detecting unit includes an angle detecting module that
is mounted on the cycle body; and said angle detecting module is
configured to detect an inclination angle of the electric cycle
with respect to a horizontal plane, the inclination angle serving
as an element of the resistance factor for determination of said
one of the starting torque values or one of the operating torque
values to serve as the assist torque value.
4. The assistance system as claimed in claim 1, wherein: said
resistance detecting unit includes a wind detecting module that is
configured to detect wind resistance received by the electric cycle
to serve as an element of the resistance factor; said database is
further configured to store a plurality of compensatory torque
values each of which corresponds to a respective one of ranges of
values of the wind resistance detected by said resistance detecting
unit; and said controller is configured to determine one of the
compensatory torque values based on the wind resistance detected by
said wind detecting module, and to calculate a sum of said one of
the compensatory torque values and the assist torque value to
obtain the compensated torque value.
5. The assistance system as claimed in claim 1, wherein: said
resistance detecting unit includes a road designating module that
is configured to be operated to designate a road surface condition
which serves as an element of the resistance force factor for
determination of said one of the starting torque values or one of
the operating torque values to serve as the assist torque
value.
6. The assistance system as claimed in claim 1, wherein: said
resistance detecting unit includes a load designating module that
is configured to be operated to designate a loaded weight which
serves as an element of the resistance factor for determination of
said one of the starting torque values or one of the operating
torque values to serve as the assist torque value.
7. The assistance system as claimed in claim 1, wherein: said
setting interface is configured to be operated for input of a
resistance torque value which corresponds to torque for hindering
the rotation of the driving wheel; and said controller being
configured to, when said controller is switched to the aided mode,
control said torque motor to exert torque to the driving wheel
based on the output torque value thus calculated, and when said
controller is switched to the exercise mode, control said torque
motor to exert torque to the driving wheel based on the resistance
torque value.
8. The assistance system as claimed in claim 1, further comprising:
a brake-lever mounted on the cycle body, communicable with said
controller, and configured to be operated to trigger said
controller to halt power-aid of the torque motor.
9. The assistance system as claimed in claim 1, wherein the torque
motor is an integrated hub motor mounted on the driving wheel or a
mid-drive motor coupled to the cycle drivetrain.
10. The assistance system as claimed in claim 1, wherein the torque
motor is an electric motor which is capable of driving rotation of
the driving wheel.
11. The assistance system as claimed in claim 1, wherein said
torque calculation unit further includes a setting interface
configured to be operated for input of an assist ratio that is used
by said controller to control the torque motor to drive the
rotation of the driving wheel based on the assist ratio.
12. The assistance system as claimed in claim 1, wherein said
torque calculation unit further includes a setting interface
configured to be operated for input of setting torque values that
are used to replace the starting torque values and the operating
torque values stored in the database.
13. The assistance system as claimed in claim 1, the driving wheel
being a rear wheel of the electric cycle, wherein said controller
is configured to control the torque motor to drive the rotation of
the rear wheel based on the output torque value.
14. The assistance system as claimed in claim 1, the driving wheel
being a front wheel of the electric cycle, wherein said controller
is configured to control the torque motor to drive the rotation of
the front wheel based on the output torque value.
Description
FIELD
The disclosure relates to an assistance system, and more
particularly to an assistance system for facilitating operation of
an electric cycle.
BACKGROUND
To ride an electric bicycle on a local bikeway in the European
Union or Japan, a power assist ratio, that is a ratio of electric
propulsion power to rider-pedaling power, must meet local
regulations. Therefore, with regard to conventional design of
auxiliary propulsion power control of an electric bicycle, which
may be a product of Bosch in Germany, or Panasonic, Yamaha, or
Shimano in Japan, a cyclist has to set the assist ratio prior to
starting riding of the electric bicycle. During riding such kind of
the electric bicycle, a torque detector is used to detect rider's
pedaling torque in real time, and provides a result of detection to
a controller of the electric bicycle for determining a value of the
electric propulsion power corresponding to rider's pedaling torque.
For example, an assist ratio that is set to have a value of 75%
means that human pedal power of pedaling the electric bicycle
should exceed 25 percent of the total power of propelling the
electric bicycle, and the electric propulsion power is restricted
to be at most 75 percent of the total power of propelling the
electric bicycle.
Moreover, the conventional design of auxiliary propulsion power
control does not take into account resistance factors that work
against forward movement of the electric bicycle, e.g., moving
against the wind, climbing a hill, riding with a heavy load, or
poor road surface. In addition, the conventional design of
auxiliary propulsion power control usually adopts a feed-afterward
control scheme where the rider must exert force before the
power-assist force is involved, resulting in a latency of response
in the auxiliary propulsion power control.
SUMMARY
Therefore, an object of the disclosure is to provide an assistance
system for facilitating operation of an electric cycle that can
alleviate at least one of the drawbacks of the prior art.
According to the disclosure, the electric cycle includes a cycle
body, a driving wheel, a cycle drivetrain, a battery, and a torque
motor adapted to exert torque to the driving wheel. The assistance
system is to be mounted on the cycle body and to be electrically
connected to the battery and the torque motor. The assistance
system includes a resistance detecting unit, a database, a torque
calculation unit and a torque-control handlebar grip.
The resistance detecting unit is configured to obtain a resistance
factor that works against forward movement of the electric
cycle.
The database is configured to store a set of starting torque values
each of which is a value of torque for initiating rotation of the
driving wheel from a standstill under influence of the resistance
factor, and a set of operating torque values each of which is a
value of torque for maintaining the rotation of the driving wheel
at a constant rotational speed under the influence of the
resistance factor.
The torque calculation unit includes a controller switchable
between an aided mode and an exercise mode.
The torque-control handlebar grip is configured to be operated to
trigger an assigned gain and to tune the assigned gain that is to
be provided to the torque calculation unit.
The controller is configured to, when the controller is switched to
the aided mode, determine one of the starting torque values or one
of the operating torque values based on the resistance factor
obtained by the resistance detecting unit to serve as an assist
torque value. The controller is configured to calculate a
compensated torque value based on the assist torque value and the
resistance factor obtained by the resistance detecting unit. The
controller is configured to multiply the compensated torque value
by the assigned gain to obtain an output torque value. The
controller is configured to control the torque motor to drive the
rotation of the driving wheel based on the output torque value.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of the disclosure will become
apparent in the following detailed description of the embodiment
(s) with reference to the accompanying drawings, of which:
FIG. 1 is a perspective view illustrating an embodiment of an
assistance system for facilitating operation of an electric cycle
according to the disclosure;
FIG. 2 is a block diagram illustrating the embodiment of the
assistance system according to the disclosure;
FIG. 3 is a schematic diagram illustrating an embodiment of
controlling a torque motor to drive rotation of a driving wheel of
the electric cycle by the assistance system according to the
disclosure;
FIG. 4 is a schematic diagram illustrating an embodiment of an
angle detecting module of a resistance detecting unit of the
assistance system according to the disclosure;
FIG. 5 is a flow chart illustrating an embodiment of an operating
procedure of the assistance system according to the disclosure;
and
FIG. 6 is a schematic diagram illustrating an embodiment of
computation of an output torque value by the assistance system
according to the disclosure.
DETAILED DESCRIPTION
Before the disclosure is described in greater detail, it should be
noted that where considered appropriate, reference numerals or
terminal portions of reference numerals have been repeated among
the figures to indicate corresponding or analogous elements, which
may optionally have similar characteristics.
Referring to FIGS. 1 and 2, an embodiment of an assistance system 4
for facilitating operation of an electric cycle 3 is illustrated.
The electric cycle 3 includes a cycle body 31, a front wheel 32 and
a rear wheel (which is a driving wheel 33) spaced apart from each
other and coupled to the cycle body 31, a cycle drivetrain 36
coupled to the cycle body 31 and the driving wheel 33, a torque
motor 34 coupled to the cycle body 31, and a battery 35 installed
on the cycle body 31. In another embodiment, the driving wheel 33
may be the front wheel 2. The cycle drivetrain 36 is to be pedaled
to drive rotation of the driving wheel 33. In one embodiment, two
torque motors 34 are respectively coupled to the cycle drivetrain
36 and the driving wheel 33. However, in this embodiment, only one
torque motor is required, and the torque motor may be coupled to
the cycle drivetrain 36 or to the driving wheel 33. The battery 35
is electrically connected to the torque motor 34 and the assistance
system 4, and is configured to supply electrical power to the
torque motor 34 and the assistance system 4. In this embodiment,
the electric cycle 3 is implemented to be an electric bicycle, but
implementation is not limited to the disclosure herein and may vary
in other embodiments.
The assistance system 4 is to be mounted on the cycle body 31 and
is to be electrically connected to the torque motor 34. Driven by
the assistance system 4, the torque motor 34 is adapted to exert
torque through the cycle drivetrain 36 to the driving wheel 33. The
torque motor 34 may be implemented to be an integrated hub motor
mounted on the driving wheel 33, a mid-drive motor coupled to the
cycle drivetrain 36, a servomotor, a step motor, a switched
reluctance motor, or any electric torque motor capable of realizing
all functions mentioned in this disclosure. However, implementation
of the torque motor 34 is not limited to the disclosure herein and
may vary in other embodiments. In addition, in one embodiment, the
electric cycle 3 includes only one torque motor 34. It should be
noted that the torque motor 34 should not burn out when the torque
motor 34 gets stuck.
The assistance system 4 includes a database 41, a resistance
detecting unit 42, a wheel speed sensor 43, a torque-control
handlebar grip 44, a brake-lever 46, and a torque calculation unit
45 that is communicable with the database 41, the resistance
detecting unit 42, the wheel speed sensor 43, the torque-control
handlebar grip 44 and the brake-lever 46.
In this embodiment, the wheel speed sensor 43 is disposed in the
torque motor 34, but disposition of the wheel speed sensor 43 is
not limited thereto. The wheel speed sensor 43 is configured to
detect a rotational speed of the driving wheel 33, and to transmit
a result of detection to the torque calculation unit 45.
The torque-control handlebar grip 44 is mounted to a handlebar of
the cycle body 31 as shown in FIG. 1, and is configured to be
operated to trigger an assigned gain and to tune the assigned gain
that is to be provided to the torque calculation unit 45 for
adjusting torque to be exerted by the torque motor 34. In this
embodiment, the torque-control handlebar grip 44 is implemented to
be operated by twisting similar to the operation of a throttle
twist grip of a motorcycle. The torque-control handlebar grip 44 is
operated by twisting to adjust a value of the assigned gain which
is proportional to an amount of twist, and may be further operated
to trigger the assistance system 4 to interact with the torque
motor 34 for facilitating operating the electric cycle 3 through
driving the torque motor 34. For example, the value of the assigned
gain is zero when a twisted angle of the torque-control handlebar
grip 44 is zero. The value of the assigned gain is increased along
with increasing twisted angle. In some cases, the value of the
assigned gain may be increased beyond 100%. In another embodiment,
the torque-control handlebar grip 44 may be operated to output a
switch signal to activate or deactivate the assistance system 4
which is configured to facilitate operation of the electric cycle
3.
The resistance detecting unit 42 is configured to obtain a
resistance factor that works against forward movement of the
electric cycle 3.
The database 41 is configured to store a plurality of starting
torque values each of which is a value of torque for initiating
rotation of the driving wheel 33 from a standstill under influence
of the resistance factor, and a plurality of operating torque
values each of which is a value of torque for maintaining the
rotation of the driving wheel 33 at a constant rotational speed
under the influence of the resistance factor. Each of the operating
torque values corresponds to a range of values of the rotational
speed of the driving wheel 33.
Specifically speaking, in this embodiment, the resistance detecting
unit 42 includes an angle detecting module 421, a wind detecting
module 422, a road designating module 423, and a load designating
module 424 that are mounted on the cycle body 31.
The angle detecting module 421 is configured to detect an
inclination angle of the cycle body 31 with respect to a horizontal
plane. The inclination angle serves as an element of the resistance
factor, and cooperates with the rotational speed of the driving
wheel 33 detected by the wheel speed sensor 43 for determination of
said one of the starting torque values or one of the operating
torque values to serve as an assist torque value. Referring to FIG.
4, in this embodiment, the angle detecting module 421 is
implemented by a combination of a gyroscope, an accelerometer, a
high-pass filter, a low-pass filter and an A/D converter. Such
implementation has been widely applied to electric balancing
vehicles, and is capable of calculating the inclination angle, and
a curvature of road surface and an acceleration of the electric
cycle as well. In one embodiment, the angle detecting module 421
may be an inclinometer, a clinometer, a tilt sensor, a tilt
indicator or a tilt meter which is able to detect the inclination
of the electric cycle 3 with respect to the horizontal plane.
Since the aforementioned implementation of the angle detecting
module 421 has been well known to one skilled in the relevant art,
detailed explanation of the same is omitted herein for the sake of
brevity.
The wind detecting module 422 is mounted on a head tube of the
cycle body as shown in FIG. 1. The wind detecting module 422 is
configured to detect wind resistance received by the head tube of
the electric cycle 3 to serve as an element of the resistance
factor. In this embodiment, the wind detecting module 422 is
implemented to be an anemometer. Specifically, the wind detecting
module 422 is a digital vane anemometer available on the market,
but implementation thereof is not limited to the disclosure herein
and may vary in other embodiments.
The road designating module 423 is configured to be operated to
designate a road surface condition which serves as an element of
the resistance factor for determination of said one of the starting
torque values or one of the operating torque values to serve as the
assist torque value. The road surface condition may be implemented
to be associated with roads of asphalt pavement, soil surface,
concrete surface, gravel surface, irregular surface and so on.
The load designating module 424 is configured to be operated to
designate a loaded weight which serves as an element of the
resistance factor for determination of said one of the starting
torque values or one of the operating torque values to serve as the
assist torque value. The loaded weight is associated with a weight
of total load on the electric cycle 3.
In this embodiment, the database 41 stores a plurality of
assist-torque lookup tables. One of the assist-torque lookup tables
is configured to be selected among the plurality of assist-torque
lookup tables based on the road surface condition thus designated
and the loaded weight thus designated to serve as a working lookup
table for determination of the assist torque value. Moreover, for
each of the assist-torque lookup tables, a combination of a value
of the rotational speed thus detected and a value of the
inclination angle thus detected can be utilized to look up the
assist torque value (A3) in the assist-torque lookup table (see
FIG. 6), wherein the starting torque values are elements contained
in the assist-torque lookup tables and corresponding to the
rotational speed that is of a zero value, and the operating torque
values are other elements contained in the assist-torque lookup
tables and corresponding to the rotational speed that is of nonzero
values.
Furthermore, the database 41 is configured to store a plurality of
compensatory torque values (A4) each of which corresponds to a
respective one of ranges of values of the wind resistance detected
by the resistance detecting unit 42.
It should be noted that the starting torque values and the
operating torque values stored in the database 41 are predetermined
by a cycle manufacturer based on statistics of experiment results
which are gathered from intensive tests performed on each target
model of the electric cycle 3. The intensive tests are performed
according to traffic regulation testing standard of local
government. Therefore, the assistance system 4 is capable of
precisely regulating operation of the electric cycle 3.
The torque calculation unit 45 includes a controller 451 switchable
between an aided mode and an exercise mode. The torque calculation
unit 45 further includes a setting interface 450. The controller
451 may be implemented to be a microcontroller, a system on a chip
(SoC), one or more central processing units (CPU) or integrated
circuit (IC) chips configured to carry out the functions discussed
in this disclosure. The setting interface 450 includes a screen and
a button set. The setting interface 450 is configured to be
operated for input of an assist ratio that is a ratio of auxiliary
propulsion power to human pedal power. In one embodiment, the
assist ratio thus inputted can be utilized by the controller 451 to
control the torque motor 34 to drive rotation of the driving wheel
33 based on the assist ratio. In one embodiment, the setting
interface 450 may be further operated for input of setting torque
values that are used to replace a corresponding portion of what are
stored in the database 41. The assist ratio should be assigned to
comply with local regulations or laws of a region (e.g., the
European Union region), and can be arbitrarily assigned whenever no
restriction is imposed on the assist ratio. For example, to comply
with regulations in Japan and the European Union regions, the
assist ratio may be assigned such that auxiliary propulsion power
and human pedal power respectively account for 75% and 25% of total
power for propelling the electric cycle 3. In addition, for
entertainment or exercise, a cyclist may be able to increase a
percentage that the human pedal power accounts for by adjusting the
assist ratio. For example, the assist ratio is changed such that
the auxiliary propulsion power and the human pedal power
respectively account for 60% and 40% of the total power.
Moreover, the setting interface 450 is configured to be operated
for input of a resistance torque value which corresponds to torque
for hindering the rotation of the driving wheel 33.
In one embodiment, the setting interface 450, the road designating
module 423 and the load designating module 424 are implemented to
be an integrated input device that includes button(s) or a touch
screen for touch input, a microphone for audio input and/or a
camera for video input. The integrated input device may be mounted
to the handlebar of the cycle body 31 as the setting interface 450
shown in FIG. 1.
The brake-lever 46 is mounted on the handlebar of the cycle body
31, and is communicable with the controller 451. The brake-lever 46
is configured to be operated, e.g., by pulling the brake-lever 46
similar to pulling a brake brake-lever of a regular bicycle, to
trigger the controller 451 to halt power-aid of the torque motor
34. When the brake-lever 46 is released, the operation of the
torque motor 34 resumes.
Referring to FIGS. 3, 5 and 6, an example of operating the
assistance system 4 according to the disclosure is described as
follows. As shown in FIG. 5, when the assistance system 4 is turned
on, the cyclist is requested to select the aided mode or the
exercise mode of the controller 451. When the controller 451 is
switched to the aided mode, the assistance system 4 receives inputs
of the road surface condition and the loaded weight designated by
the rider, and proceeds to perform initialization. Any one of the
road surface condition and the loaded weight that is not designated
by the cyclist in a predetermined duration is automatically
assigned a default value by the assistance system 4, and
initialization is automatically performed afterward. Each of the
road surface condition and the loaded weight may be designated (see
annotation A1 in FIG. 6) by the cyclist via a corresponding one of
the road designating module 423 and the load designating module
424, or may be designated to the default value when the
predetermined duration has elapsed. In addition, the angle
detecting module 421 is automatically providing inclination angle
to the assistance system 4 (see annotation 3-1 in FIG. 6) with the
aid of the angle detecting module 421 which is implemented by at
least the gyroscope and the accelerometer as shown in FIG. 4.
Thereafter, a flow of operating procedure enters into a work cycle
of the aided mode that is executed at high frequency. At the
beginning of the work cycle of the aided mode, the wheel speed
sensor 43 detects the rotational speed of the driving wheel 33 (see
annotation 3-2 in FIG. 6), and the wind detecting module 422
detects the wind resistance.
At the same time, as shown in FIG. 6, the controller 451 is
configured to select one of the assist-torque lookup tables (A2)
based on the road surface condition designated by the road
designating module 423 and the loaded weight designated by the load
designating module 424, and then to determine the assist torque
value (A3) based on the rotational speed of the driving wheel 33
detected by the wheel speed sensor 43 and the inclination angle
obtained by the angle detecting module 421 from said one of the
assist-torque lookup tables selected by the controller 451. The
assist torque value is one of the starting torque values when the
rotational speed of the driving wheel 33 thus detected is equal to
zero, and is one of the operating torque values when the rotational
speed of the driving wheel 33 thus detected is not equal to zero.
Moreover, the controller 451 is configured to determine one of the
compensatory torque values (A4) based on the wind resistance
detected by the wind detecting module 422, and to calculate a sum
of said one of the compensatory torque values thus determined and
the assist torque value determined by the controller 451 to serve
as a compensated torque value.
The controller 451 is further configured to calculate an output
torque value (A6) for driving the torque motor 34 by multiplying
the compensated torque value by the assigned gain (A5) which may be
designated by the cyclist in real time. It is noted that, the road
surface condition, the loaded weight, the wind resistance, the
assist torque value, the compensatory torque value, the assigned
gain, and the output torque value may vary in real time.
Thereafter, in a condition that the brake-lever 46 is not operated,
the controller 451 is configured to control a power converter,
which is supplied with electrical power of the battery 35 by means
of pulse width modulation (PWM) techniques, so as to enable the
torque motor 34 to exert torque to the driving wheel 33 for driving
the rotation of the driving wheel 33 in real time based on the
output torque value thus calculated. When the brake-lever 46 is
operated, the controller 451 controls the power converter to stop
driving the torque motor 34, so no torque is exerted to the driving
wheel 33 by the torque motor 34. When the brake-lever 46 is
released, the work cycle of the aided mode resumes. The work cycle
of the aided mote repeats until the assistance system 4 is turned
off. It should be noted that the assistance system 4 may turn off
when an abnormal emergency or an error occurs.
On the other hand, when the controller 451 is switched to the
exercise mode, the controller 451 is configured to control the
torque motor 34 to exert torque to the driving wheel 33 based on
the resistance torque value. In addition, when the controller 451
is switched to the exercise mode, the assist ratio can be assigned
via the setting interface to be a negative value so as to create a
handicap for pedaling of the electric cycle 3.
In summary, the assistance system 4 according to the disclosure
utilizes the wheel speed sensor 43 to obtain the rotational speed
of the driving wheel 33, utilizes the resistance detecting unit 42
to obtain the external resistance factors (e.g., the inclination
angle, the wind resistance, the road surface condition and the
loaded weight), utilizes the setting interface 450 to set the
assist ratio with a rider-friendly value, and utilizes the
torque-control handlebar grip 44 to tune the assigned gain as
desired. The assistance system 4 further utilizes the torque
calculation unit 45 to look up, via the database 41, the assist
torque value (for compensating influence of the inclined road and
the loaded weight) and the compensatory torque value (for
compensating influence of headwind), to calculate the compensated
torque value by summing the compensatory torque value and the
assist torque value, to calculate the output torque value based on
a product of the compensated torque value and the assigned gain,
and to control the torque motor 34 to drive rotation of the driving
wheel 33 based on the output torque value.
The assistance system 4 according to the disclosure has many
features described as follows. First, the starting torque values,
the operating torque values and the compensatory torque values
stored in the database 41 are predetermined by a cycle manufacturer
based on statistics of experiment results gathered from field tests
that are performed on the target model of the electric cycle 3 and
that are performed according to governments-recognized standard
conditions, and are reliable and practical. Second, since the
output torque value is obtained according to a pre-established
database, complexity of calculating the output torque value is low,
resulting in efficiency of control. Third, the design of auxiliary
propulsion power control of the assistance system 4 according to
the disclosure adopts a feed-forward control scheme, so the
auxiliary propulsion power may be provided prior to exertion of the
rider's pedaling power, facilitating riding of the electric cycle
8. Fourth, the cyclist is able to adjust the output torque as
desired by varying the assist ratio and the assign gain through
operating the setting interface 450 and twisting the torque-control
handlebar grip 44, respectively. As a result, a complex and
expensive pedal torque sensor which is usually needed on a
conventional electric bicycle may be omitted. The cyclist is able
to ride the electric cycle 3 aided by the assistance system 4 of
this disclosure with ease and without worrying about effects of
strong wind and steep slopes.
In the description above, for the purposes of explanation, numerous
specific details have been set forth in order to provide a thorough
understanding of the embodiments. It will be apparent, however, to
one skilled in the art, that one or more other embodiments may be
practiced without some of these specific details. It should also be
appreciated that reference throughout this specification to "one
embodiment," "an embodiment," an embodiment with an indication of
an ordinal number and so forth means that a particular feature,
structure, or characteristic may be included in the practice of the
disclosure. It should be further appreciated that in the
description, various features are sometimes grouped together in a
single embodiment, figure, or description thereof for the purpose
of streamlining the disclosure and aiding in the understanding of
various inventive aspects, and that one or more features or
specific details from one embodiment may be practiced together with
one or more features or specific details from another embodiment,
where appropriate, in the practice of the disclosure.
While the disclosure has been described in connection with what are
considered the exemplary embodiments, it is understood that this
disclosure is not limited to the disclosed embodiments but is
intended to cover various arrangements included within the spirit
and scope of the broadest interpretation so as to encompass all
such modifications and equivalent arrangements.
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